Adhesive layer and flexible display device

Abstract

The invention relates to the technical field of display, in particular to an adhesive layer and a flexible display device. The adhesive layer comprises a first adhesive sub-layer, a second adhesive sub-layer and a supporting sub-layer located between the first adhesive sub-layer and the second adhesive sub-layer. The first bonding sub-layer comprises a first bending part located in the bending area, and the first bending part comprises first bonding sub-parts and first supporting sub-parts which are alternately arranged; the elastic modulus of the first supporting sub-part is larger than that of the first bonding sub-part, and the elastic modulus of the first supporting sub-part is smaller than that of the supporting sub-layer. The second bonding sub-layer comprises a second bending part located in the bending area, and the second bending part comprises second bonding sub-parts and second supporting sub-parts which are alternately arranged; the elastic modulus of the second supporting sub-part is larger than that of the second bonding sub-part, and the elastic modulus of the second supporting sub-part is smaller than that of the supporting sub-layer. The adhesive layer provided by the invention not only can have relatively good adhesion, but also can have relatively good recovery performance.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more particularly to an adhesive layer and a flexible display device. Background Technology

[0002] As flexible display technology matures, foldable flexible display devices (such as foldable phones, foldable tablets, or foldable computers) will be a major future trend; the display portion of these foldable devices is foldable. Compared to traditional display devices, these foldable devices allow for switching of the physical size of the display, greatly improving the user experience.

[0003] However, existing flexible display devices are prone to creases at the folding points, which affects the display effect of the foldable screen. Summary of the Invention

[0004] To address the aforementioned technical problems, this disclosure provides an adhesive layer and a flexible display device.

[0005] In a first aspect, this disclosure provides an adhesive layer. The adhesive layer can be applied to a flexible display device having a bending region and a non-bending region located on at least one side of the bending region. The bending region includes a bending axis extending along a first direction. The adhesive layer includes: a first adhesive sublayer, a second adhesive sublayer, and a support sublayer, with the support sublayer located between the first adhesive sublayer and the second adhesive sublayer. The first adhesive sublayer includes a first bending portion located in the bending region, and along a second direction, the first bending portion includes alternating first adhesive sub-parts and first support sub-parts. The elastic modulus of the first support sub-part is greater than the elastic modulus of the first adhesive sub-part, and the elastic modulus of the first support sub-part is less than the elastic modulus of the support sublayer. The second adhesive sublayer includes a second bending portion located in the bending region, and along the second direction, the second bending portion includes alternating second adhesive sub-parts and second support sub-parts. The elastic modulus of the second support sub-part is greater than the elastic modulus of the second adhesive sub-part, and the elastic modulus of the second support sub-part is less than the elastic modulus of the support sublayer. The second direction intersects with the first direction, and the second direction also intersects with the thickness direction of the adhesive layer.

[0006] Secondly, this disclosure provides a display device. The display device includes a plurality of functional layers and at least one adhesive layer, wherein at least two adjacent functional layers are bonded together by the adhesive layer. The adhesive layer can be any of the adhesive layers provided in the first aspect.

[0007] The technical solution provided in this disclosure has the following advantages compared with the prior art: through low thickness in the adhesive layer direction... high The low-layer structure, combined with the alternating arrangement of adhesive sub-parts (first adhesive sub-part and second adhesive sub-part) and support sub-parts (first support sub-part and second support sub-part) in the horizontal direction of the adhesive layer, can not only ensure stable adhesion between the adhesive layer and the surrounding film layer, but also effectively disperse the bending stress in the corresponding part of the bending area, improve the deformation recovery ability of the adhesive layer, and reduce the probability of creases in the corresponding part of the bending area; at the same time, it can also enhance the impact resistance of the adhesive layer, improve bending performance, and extend the overall service life of the product. Attached Figure Description

[0008] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0009] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of a flexible display device provided in an embodiment of the present disclosure; Figure 2 A cross-sectional view of an adhesive layer provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of the structure of a first adhesive sublayer provided in an embodiment of the present disclosure; Figure 4 This is a schematic diagram of the structure of a second adhesive sublayer provided in an embodiment of the present disclosure; Figure 5 This is a schematic diagram of another first adhesive sublayer provided in an embodiment of the present disclosure; Figure 6 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure; Figure 7 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure; Figure 8 This is a schematic diagram of another second adhesive sublayer provided in an embodiment of the present disclosure; Figure 9 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure; Figure 10 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure; Figure 11 A cross-sectional view of another adhesive layer provided in an embodiment of this disclosure; Figure 12A cross-sectional view of another adhesive layer provided in an embodiment of this disclosure; Figure 13 A cross-sectional view of another adhesive layer provided in an embodiment of this disclosure; Figure 14 A cross-sectional view of another adhesive layer provided in an embodiment of this disclosure; Figure 15 This is a cross-sectional view of a display device provided in an embodiment of the present disclosure. Detailed Implementation

[0011] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0012] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0013] In order to ensure the adhesion between the adhesive material used in existing flexible display devices and the surrounding film layers, the adhesive material often has to sacrifice its own bending recovery ability, which will greatly increase the probability of creases at the folding points of the device and make the crease problem more serious.

[0014] Figure 1 This is a schematic diagram of the structure of a flexible display device provided in an embodiment of the present disclosure.

[0015] Based on this, such as Figure 1 As shown, some embodiments of this disclosure provide an adhesive layer. The adhesive layer can be applied to a flexible display device 200. The flexible display device 200 has a bending region F1 and a non-bending region F2 located on at least one side of the bending region F1. The bending region F1 includes a bending axis O extending along a first direction X.

[0016] In some examples, adhesive layer 100 is either optically clear adhesive (OCA) or pressure-sensitive adhesive (PSA).

[0017] Because OCA and PSA have good light transmittance, bonding stability and flexibility, they can meet the optical performance and bonding requirements of flexible display devices. At the same time, they are not prone to cracking or debonding during repeated bending, and can be used for adhesive layer 100.

[0018] It should be noted that the above adhesive material is only an example, and the material selection of adhesive layer 100 is not limited to this. Other suitable adhesive materials can also be selected according to actual usage requirements.

[0019] Figure 2 This is a cross-sectional view of an adhesive layer provided in an embodiment of this disclosure.

[0020] Combination Figure 1 and Figure 2 As shown, in some embodiments, along the third direction Z, the adhesive layer 100 includes: a first adhesive sublayer 10, a second adhesive sublayer 20, and a support sublayer 30, wherein the support sublayer 30 is located between the first adhesive sublayer 10 and the second adhesive sublayer 20.

[0021] The elastic modulus of the support sublayer 30 is greater than that of the first adhesive sublayer 10, and the elastic modulus of the support sublayer 30 is greater than that of the second adhesive sublayer 20, so that the adhesive layer 100 forms a low-high-low stacked structure in the third direction Z.

[0022] As designed above, the adhesive layer 100 can achieve stable adhesion to the surrounding film layer using the first adhesive sub-layer 10 and the second adhesive sub-layer 20 on both the upper and lower sides, giving the adhesive layer 100 good adhesion performance. Simultaneously, the middle high-elasticity modulus support sub-layer 30 can be used as an impact-resistant enhancement layer for the adhesive layer 100, effectively strengthening its overall impact resistance. This ensures that the adhesive layer 100 has good impact resistance while maintaining good adhesion performance.

[0023] Furthermore, the first adhesive sublayer 10 includes a first bent portion 11 located in the bending region F1. Along the second direction Y, the first bent portion 11 includes alternating first adhesive sub-parts 111 and first support sub-parts 112. The elastic modulus of the first support sub-part 112 is greater than that of the first adhesive sub-part 111, and the elastic modulus of the first support sub-part 112 is less than that of the support sublayer 30.

[0024] The second adhesive sublayer 20 includes a second bent portion 21 located in the bending region F1. Along the second direction Y, the second bent portion 21 includes alternately arranged second adhesive sub-parts 211 and second support sub-parts 212. The elastic modulus of the second support sub-part 212 is greater than that of the second adhesive sub-part 211, and the elastic modulus of the second support sub-part 212 is less than that of the support sublayer 30.

[0025] Wherein, the second direction Y intersects the first direction X, and the second direction Y also intersects the third direction Z. The third direction Z is the thickness direction of the adhesive layer 100. For example, the second direction Y is perpendicular to the first direction X, and the second direction Y is perpendicular to the third direction Z.

[0026] Based on this, a recovery rate enhancement zone can be constructed at the first bending portion 11 and the second bending portion 21 corresponding to the bending area F1 of the adhesive layer 100. This ensures the bonding performance of the first bending portion 11 and the second bending portion 21 through the low-modulus first adhesive sub-part 111 and the second adhesive sub-part 211, while enhancing the deformation recovery capability of the first bending portion 11 and the second bending portion 211 through the medium-modulus first support sub-part 112 and the second support sub-part 212, thus meeting the high recovery rate requirement for crease improvement in the bending area F1. Simultaneously, setting the elastic modulus of the first support sub-part 112 and the second support sub-part 212 to be lower than the elastic modulus of the support sub-layer 30 allows the modulus gradient setting of the first support sub-part 112 and the second support sub-part 212 with that of the support sub-layer 30 to synergize with the low-high-low stacked structure along the third direction Z. This achieves a balance between bonding performance and bending recovery capability, while further enhancing the overall impact resistance of the adhesive layer 100 through the support sub-layer 30.

[0027] In summary, the adhesive layer 100 provided in this embodiment, through a low-high-low stacked structure in the third direction Z, combined with the design of alternately arranged support sub-parts and adhesive sub-parts in the second direction Y, can maintain the stable adhesion performance between the adhesive layer 100 and the surrounding film layer, effectively disperse the bending stress in the bending area F1, improve the deformation recovery ability of the adhesive layer, and reduce the probability of creases occurring in the bending area F1 of the flexible display device; at the same time, it can also enhance the impact resistance of the adhesive layer 100, improve the bending performance of the adhesive layer, and extend the overall service life of the flexible display device.

[0028] In some examples, the elastic modulus of the support sublayer 30 can be between 200 kPa and 500 kPa. Within the range of 200 kPa to 500 kPa, the support sublayer 30 can provide good impact resistance while also meeting bending requirements, which is beneficial to improving the overall structural stability and bending durability of the adhesive layer 100.

[0029] For example, the elastic modulus of the support sublayer 30 can be any one of 200 kPa, 250 kPa, 300 kPa, 350 kPa, 400 kPa, 450 kPa, or 500 kPa. However, the elastic modulus of the support sublayer 30 is not limited to this in the embodiments of this disclosure.

[0030] In some examples, the elastic modulus of the first adhesive sub-part 111 and / or the second adhesive sub-part 211 can be 20 kPa to 50 kPa.

[0031] Within the range of 20 kPa to 50 kPa, the first adhesive sub-part 111 and the second adhesive sub-part 211 can have good adhesion, which can reduce the probability of interface debonding during bending and improve the adhesion reliability between adjacent film layers.

[0032] For example, the elastic modulus of the first adhesive sub-part 111 and / or the second adhesive sub-part 211 can be any one of 20 kPa, 25 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa or 50 kPa. However, the elastic modulus of the first adhesive sub-part 111 and the second adhesive sub-part 211 is not limited thereto in the embodiments of this disclosure.

[0033] In some examples, the elastic modulus of the first support sub-part 112 and / or the second support sub-part 212 can be 50 kPa to 200 kPa.

[0034] Within the range of 50kPa to 200kPa, the first support sub-part 112 and the second support sub-part 212 can provide good deformation recovery capability, while adapting to bending action, reducing residual marks after bending, and improving the overall bending performance of the adhesive layer 100.

[0035] For example, the elastic modulus of the first support sub-part 112 and / or the second support sub-part 212 can be any value among 50 kPa, 80 kPa, 100 kPa, 120 kPa, 150 kPa, 180 kPa, or 200 kPa. However, the elastic modulus of the first support sub-part 112 and the second support sub-part 212 are not limited thereto in the embodiments of this disclosure.

[0036] Figure 3 This is a schematic diagram of the structure of a first adhesive sublayer provided in an embodiment of the present disclosure. Figure 4 This is a schematic diagram of the structure of a second adhesive sublayer provided in an embodiment of the present disclosure.

[0037] Combination Figure 3 and Figure 4 As shown, in some embodiments, the bending region F1 includes two first regions F11 located on both sides of the bending axis O.

[0038] Both first regions F11 are provided with first support sub-parts 112, and the first support sub-parts 112 in both first regions F11 are symmetrically arranged along the bending axis O; and / or, both first regions F11 are provided with second support sub-parts 212, and the second support sub-parts 212 in both first regions F11 are symmetrically arranged along the bending axis O.

[0039] The arrangement structure of the first support sub-part 112 and the second support sub-part 212 described above can include the following three cases: The first type: such as Figure 3 As shown, both first regions F11 are provided with first support sub-parts 112, and the first support sub-parts 112 in the two first regions F11 are symmetrically arranged along the bending axis O. In other words, the first support sub-parts 112 located in the two first regions F11 in the first bending portion 11 can form a structure symmetrical about the bending axis O.

[0040] Based on this, the stress distribution of the first region F11 on both sides of the bending axis O of the first bending part 11 can be more balanced, reducing local stress concentration, reducing the risk of permanent deformation of the adhesive layer 100, and thus improving the crease problem of the bending area F1.

[0041] The second type: such as Figure 4 As shown, both first regions F11 are provided with second support sub-parts 212, and the second support sub-parts 212 in the two first regions F11 are symmetrically arranged along the bending axis O. In other words, the second support sub-parts 212 located in the two first regions F11 in the second bending portion 21 can form a structure symmetrical about the bending axis O.

[0042] Based on this, the stress distribution of the first region F11 on both sides of the bending axis O of the second bending part 21 can be more balanced, reducing local stress concentration, reducing the risk of permanent deformation of the adhesive layer 100, and thus improving the crease problem of the bending area F1.

[0043] The third type, combining Figure 3 and Figure 4 As shown, both first regions F11 are provided with first support sub-parts 112, and the first support sub-parts 112 in the two first regions F11 are symmetrically arranged along the bending axis O. Furthermore, both first regions F11 are provided with second support sub-parts 212, and the second support sub-parts 212 in the two first regions F11 are symmetrically arranged along the bending axis O. In other words, the first support sub-parts 112 of the first bent portion 11 and the second support sub-parts 212 of the second bent portion 21 are symmetrically arranged along the bending axis O in the two first regions F11, respectively.

[0044] Based on this, the symmetrical arrangement of the upper and lower double layers can make the stress transmission in the bending area F1 more uniform during the bending process, which is conducive to optimizing the stress distribution of the adhesive layer 100 in the bending state, improving the structural stability and deformation recovery ability of the adhesive layer 100, and thus improving the crease problem in the bending area F1.

[0045] It should be noted that a first support sub-part 112 is provided in both first regions F11. The first support sub-parts 112 in the two first regions F11 can be independent and separate from each other, or they can be the same integral structure located in different regions. This embodiment does not impose any particular limitation on this, as long as the first support sub-parts 112 are provided in both first regions F11 and are symmetrically arranged along the bending axis O.

[0046] Figure 5 This is a schematic diagram of another first adhesive sublayer provided in an embodiment of the present disclosure.

[0047] like Figure 5As shown, in some embodiments, the shape of the first support sub-part 112 can be a broken line shape.

[0048] Based on this, the first support sub-parts 112 in the two first regions F11 are symmetrically arranged along the bending axis O. At this time, the first support sub-parts 112 in the two first regions F11 together form a hollow rhombus string structure, that is, it is composed of multiple rhombus units arranged along the bending axis O, and each rhombus unit has a hollow interior.

[0049] Furthermore, the shape of the first support sub-part 112 can be further optimized to be wavy. Specifically, each corner of the first support sub-part 112 can be set as a smoothly transitioning rounded corner or arc to avoid stress concentration caused by local small sharp structures, thereby further optimizing the stress transmission in the bending area and improving the anti-crease performance of the bending area F1.

[0050] It should be noted that, Figure 5 Taking the first support sub-part 112 as an example, the shape of the second support sub-part 212 can be the same as the shape of the first support sub-part 112. Therefore, the shape of the second support sub-part 212 can be referenced. Figure 5 The shape of the first support sub-part 112 shown will not be described again here. In addition, this embodiment of the present disclosure only uses the first support sub-part 112 and the second support sub-part 212, which are in the shape of a broken line or a wave, as examples for description, but the shapes of the first support sub-part 112 and the second support sub-part 212 provided in this embodiment of the present disclosure are not limited to this.

[0051] It is understood that in some other embodiments, the shape of the second support sub-part 212 may be different from the shape of the first support sub-part 112, and the shape of the second support sub-part may also adopt the shape described in other embodiments (including but not limited to the shapes mentioned above). For example, the shape of the second support sub-part may be set as a strip.

[0052] Combination Figure 3 and Figure 4 As shown, in some embodiments, the first support sub-part 112 is an axisymmetric structure, and the axis of symmetry of the first support sub-part 112 is parallel to the bending axis O; and / or; the second support sub-part 212 is an axisymmetric structure, and the axis of symmetry of the second support sub-part 212 is parallel to the bending axis O.

[0053] The arrangement structure of the first support sub-part 112 and the second support sub-part 212 described above can include the following three cases: The first type, such as Figure 3 As shown, the first support sub-part 112 has an axisymmetric structure, and the axis of symmetry of the first support sub-part 112 is parallel to the bending axis O.

[0054] Based on this, on the one hand, the axisymmetric structure ensures that the force and deformation trajectory on both sides of the first support sub-part 112 remain consistent during bending, improving the local force offset caused by structural asymmetry. This helps reduce bending resistance during bending and makes the bending action smoother. On the other hand, the design that the axis of symmetry of the first support sub-part 112 is parallel to the bending axis O allows the first support sub-part 112 to always conform to the curvature of the adhesive layer 100 during bending, reducing the shear stress between the first support sub-part 112 and the surrounding structure (adhesive sub-part or surrounding film layer), and reducing deformation problems caused by uneven stress. At the same time, it also allows the internal stress of the adhesive layer 100 to be transmitted more evenly along the symmetrical path of the first support sub-part 112, which helps optimize the stress distribution of the adhesive layer 100 under bending conditions, thereby reducing deformation caused by local stress concentration in the adhesive layer 100 and improving the crease problem in the bending area F1.

[0055] In some examples, the first support sub-parts 112 can be provided in both first regions F11, and the first support sub-parts 112 in the two first regions F11 can be symmetrically arranged along the bending axis O. In this case, the first support sub-parts 112 can be set as an axisymmetric structure, and the axis of symmetry of the first support sub-parts 112 is parallel to the bending axis O.

[0056] Based on this, on the one hand, the force and deformation of the first support sub-parts 112 on both sides of the bending axis O can be made more consistent, reducing the force offset caused by structural asymmetry, which is conducive to reducing bending resistance; on the other hand, the internal stress of the adhesive layer 100 can be transmitted more evenly along the symmetrical path, optimizing the stress distribution under bending conditions, reducing the deformation caused by local stress concentration, and thus helping to improve the crease problem in the bending area F1.

[0057] The second type, such as Figure 4 As shown, the second support sub-part 212 has an axisymmetric structure, and the axis of symmetry of the second support sub-part 212 is parallel to the bending axis O.

[0058] Based on this, on the one hand, the axisymmetric structure ensures that the force and deformation trajectory on both sides of the second support sub-part 212 remain consistent during bending, improving the local force offset caused by structural asymmetry. This helps reduce bending resistance during bending and makes the bending action smoother. On the other hand, the design that the axis of symmetry of the second support sub-part 212 is parallel to the bending axis O allows the second support sub-part 212 to always conform to the curvature of the adhesive layer 100 during bending, reducing the shear stress between the second support sub-part 212 and the surrounding structure (adhesive sub-part or surrounding film layer), and reducing deformation problems caused by uneven stress. At the same time, it also allows the internal stress of the adhesive layer 100 to be transmitted more evenly along the symmetrical path of the second support sub-part 212, which helps optimize the stress distribution of the adhesive layer 100 under bending conditions, thereby reducing deformation caused by local stress concentration in the adhesive layer 100 and improving the crease problem in the bending area F1.

[0059] In some examples, the second support sub-parts 212 can be provided in both first regions F11, and the second support sub-parts 212 in the two first regions F11 can be symmetrically arranged along the bending axis O. In this case, the second support sub-parts 212 can be set as an axisymmetric structure, and the axis of symmetry of the second support sub-parts 212 is parallel to the bending axis O.

[0060] Based on this, on the one hand, the force and deformation of the second support sub-parts 212 on both sides of the bending axis O can be made more consistent, reducing the force offset caused by structural asymmetry, which is conducive to reducing bending resistance; on the other hand, the internal stress of the adhesive layer 100 can be transmitted more evenly along the symmetrical path, optimizing the stress distribution under bending conditions, reducing the deformation caused by local stress concentration, and thus helping to improve the crease problem in the bending area F1.

[0061] The third type, combining Figure 3 and Figure 4 As shown, the first support sub-part 112 has an axisymmetric structure, and the axis of symmetry of the first support sub-part 112 is parallel to the bending axis O; and the second support sub-part 212 has an axisymmetric structure, and the axis of symmetry of the second support sub-part 212 is parallel to the bending axis O.

[0062] Based on this, both the first support sub-part 112 and the second support sub-part 212 can maintain a stable symmetrical stress distribution during bending, further reducing the risk of stress shift caused by structural asymmetry and helping to reduce overall bending resistance. Simultaneously, it enables a more uniform distribution of stress within the adhesive layer 100 along a symmetrical path, reducing abnormal deformation caused by localized stress concentration, thereby better optimizing the stress performance of the bending zone F1 and helping to further improve the crease problem in the bending zone F1.

[0063] In some examples, when the first support sub-part 112 of the first bending portion 11 and the second support sub-part 212 of the second bending portion 21 are symmetrically arranged along the bending axis O in two first regions F11, the first support sub-part 112 and the second support sub-part 212 are both axisymmetric structures, and the axis of symmetry is parallel to the bending axis O.

[0064] Based on this, the force and deformation of the support sub-parts (first support sub-part 112 and second support sub-part 212) on both sides of the bending shaft O can be made more consistent, reducing force offset and bending resistance. At the same time, the stress inside the adhesive layer 100 can be evenly transmitted, optimizing stress distribution, reducing deformation caused by local stress concentration, and thus improving the crease problem in the bending area F1.

[0065] Figure 6 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure.

[0066] like Figure 6 As shown, in some embodiments, the first support sub-part 112 may include a plurality of sub-parts arranged along the first direction X, the sub-parts being "X" shaped.

[0067] Based on this, on the one hand, the cross structure of the X-shaped section can disperse bending stress in multiple directions, reduce local stress concentration, and help suppress the generation of creases in the bending area F1. On the other hand, the first support sub-section 112 is an axisymmetric structure, and its axis of symmetry is parallel to the bending axis O, which can make the force distribution on both sides of the bending axis O more balanced, further reduce the local deformation caused by uneven stress, thereby improving the generation and diffusion of creases and enhancing the crease resistance performance of the bending area F1.

[0068] It should be noted that, Figure 6 Taking the first support sub-part 112 as an example, the shape of the second support sub-part 212 can be the same as the shape of the first support sub-part 112. Therefore, the shape of the second support sub-part 212 can be referenced. Figure 6 The shape of the first support sub-part 112 shown will not be described again here. In addition, this embodiment of the present disclosure is only described using the first support sub-part 112 and the second support sub-part 212 with X-shaped divisions as examples, but the shapes of the first support sub-part 112 and the second support sub-part 212 provided in this embodiment of the present disclosure are not limited to this, and other structures that meet the requirements of axisymmetry are also applicable here, such as square, circular and other axisymmetric structures.

[0069] It is understood that in some other embodiments, the shape of the second support sub-part 212 may be different from the shape of the first support sub-part 112. The shape of the second support sub-part may also adopt the shape described in other embodiments (including but not limited to the shapes mentioned above). For example, the shape of the second support sub-part may be set as a strip or a hollowed-out rhombus, etc.

[0070] Figure 7 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure. Figure 8 This is a schematic diagram of another second adhesive sublayer provided in an embodiment of the present disclosure.

[0071] Combination Figure 7 and Figure 8 As shown, in some embodiments, the bending region F1 includes two first regions F11 respectively located on both sides of the bending axis O. Along the second direction Y, the bending region F1 includes two first edges S1 disposed opposite each other, and along the direction from the first edges S1 toward the bending axis O, the first region F11 includes a plurality of first sub-regions B1.

[0072] Along the direction from the first edge S1 to the bending axis O, the length of the first support sub-part 112 in the first sub-region B1 near the bending axis O in the first direction X is greater than the length of the first support sub-part 112 in the first sub-region B1 near the first edge S1 in the first direction X; and / or, along the direction from the first edge S1 to the bending axis O, the length of the first support sub-part 112 in the first sub-region B1 near the bending axis O in the first direction X is greater than the length of the first support sub-part 112 in the first sub-region B1 near the first edge S1 in the first direction X.

[0073] This configuration allows the first support sub-part 112 and the second support sub-part 212 near the bending axis O to have larger dimensions in the first direction X, which can significantly improve the deformation recovery capability near the bending axis O, effectively alleviate the stress concentration phenomenon in this area during bending, reduce the possibility of permanent deformation of the adhesive layer 100, thereby further improving the crease problem in the bending area F1 and improving the overall bending reliability and appearance flatness of the adhesive layer.

[0074] Combination Figure 7 and Figure 8 As shown, in some embodiments, the bending region F1 includes two first regions F11 respectively located on both sides of the bending axis O. Along the second direction Y, the bending region F1 includes two first edges S1 disposed opposite each other, and along the direction from the first edges S1 toward the bending axis O, the first region F11 includes a plurality of first sub-regions B1.

[0075] Along the direction from the first edge S1 to the bending axis O, the width of the first support sub-part 112 in the second direction Y within the first sub-region B1 near the bending axis O is greater than the width of the first support sub-part 112 in the second direction Y within the first sub-region B1 near the first edge S1; and / or, along the direction from the first edge S1 to the bending axis O, the width of the first support sub-part 112 in the second direction Y within the first sub-region B1 near the bending axis O is greater than the width of the first support sub-part 112 in the second direction Y within the first sub-region B1 near the first edge S1.

[0076] This configuration allows the first support sub-part 112 and the second support sub-part 212 near the bending axis O to have larger dimensions in the second direction Y, which can significantly improve the deformation recovery capability near the bending axis O, effectively alleviate the stress concentration phenomenon in this area during bending, reduce the possibility of permanent deformation of the adhesive layer 100, thereby further improving the crease problem in the bending area F1 and improving the overall bending reliability and appearance flatness of the adhesive layer 100.

[0077] Combination Figure 7 and Figure 8 As shown, in some embodiments, the bending region F1 includes two first regions F11 respectively located on both sides of the bending axis O. Along the second direction Y, the bending region F1 includes two first edges S1 disposed opposite each other, and along the direction from the first edges S1 toward the bending axis O, the first region F11 includes a plurality of first sub-regions B1.

[0078] Along the direction from the first edge S1 to the bending axis O, the projected area of ​​the first support sub-part 112 within the first sub-region B1 near the bending axis O on the support sub-layer 30 is greater than the projected area of ​​the first support sub-part 112 within the first sub-region B1 near the first edge S1 on the support sub-layer 30; and / or, along the direction from the first edge S1 to the bending axis O, the projected area of ​​the second support sub-part 212 within the first sub-region B1 near the bending axis O on the support sub-layer 30 is greater than the projected area of ​​the second support sub-part 212 within the first sub-region B1 near the first edge S1 on the support sub-layer 30.

[0079] The arrangement structure of the first support sub-part 112 and the second support sub-part 212 described above can include the following three cases: The first type, such as Figure 7 As shown, along the direction from the first edge S1 to the bending axis O, the projected area of ​​the first support sub-part 112 in the first sub-region B1 near the bending axis O on the support sub-layer 30 is greater than the projected area of ​​the first support sub-part 112 in the first sub-region B1 near the first edge S1 on the support sub-layer 30.

[0080] Therefore, the first support sub-part 112, located near the bending axis O, has a larger projected area, enabling it to provide stronger deformation recovery force to that area. Consequently, it can provide stronger structural support and deformation recovery capability in the area where stress is concentrated near the bending axis O, which helps reduce the risk of permanent deformation of the adhesive layer 100 and thus alleviates the crease problem in the bending area F1.

[0081] In some examples, the projected area of ​​the first support sub-part 112 in each first sub-region B1 on the support sub-layer 30 can gradually increase along the direction from the first edge S1 to the bending axis O.

[0082] Understandably, the bending stress in the bending zone F1 gradually increases from the first edge S1 towards the bending axis O. Therefore, the projected area of ​​the first support sub-part 112 gradually increases accordingly, which can adapt to this stress distribution. This is beneficial for providing stronger structural support and deformation recovery capability in the area where the bending stress of the first adhesive sub-layer 10 is relatively higher, thereby helping to reduce the generation of creases in the bending zone F1, while ensuring the overall structural stability of the first adhesive sub-layer 10 during bending.

[0083] The second type, such as Figure 8 As shown, along the direction from the first edge S1 to the bending axis O, the projected area of ​​the second support sub-part 212 in the first sub-region B1 near the bending axis O on the support sub-layer 30 is greater than the projected area of ​​the second support sub-part 212 in the first sub-region B1 near the first edge S1 on the support sub-layer 30.

[0084] Therefore, the second support sub-part 212, located near the bending axis O, has a larger projected area, enabling it to provide stronger deformation recovery force to that area. Consequently, it can provide stronger structural support and deformation recovery capability in the stress-concentrated area near the bending axis O, which helps reduce the risk of permanent deformation of the adhesive layer 100 and thus mitigates the crease problem in the bending area F1.

[0085] In some examples, the projected area of ​​the second support sub-part 212 within each first sub-region B1 on the support sub-layer 30 can gradually increase along the direction from the first edge S1 to the bending axis O.

[0086] Understandably, the bending stress in the bending zone F1 gradually increases from the first edge S1 towards the bending axis O. Therefore, the projected area of ​​the second support sub-part 212 gradually increases accordingly, which can match this stress distribution. This is beneficial for providing stronger structural support and deformation recovery capability in the area of ​​the second adhesive sub-layer 20 where the bending stress is relatively higher, thereby helping to reduce the generation of creases in the bending zone F1, while ensuring the overall structural stability of the second adhesive sub-layer 20 during bending.

[0087] The third type, combining Figure 7 and Figure 8 As shown, in the direction from the first edge S1 to the bending axis O, the projected area of ​​the first support sub-part 112 within the first sub-region B1 near the bending axis O on the support sub-layer 30 is greater than the projected area of ​​the first support sub-part 112 within the first sub-region B1 near the first edge S1 on the support sub-layer 30. Furthermore, in the direction from the first edge S1 to the bending axis O, the projected area of ​​the second support sub-part 212 within the first sub-region B1 near the bending axis O on the support sub-layer 30 is greater than the projected area of ​​the second support sub-part 212 within the first sub-region B1 near the first edge S1 on the support sub-layer 30.

[0088] Based on this, both the first support sub-part 112 and the second support sub-part 212 near the bending axis O have larger projected areas, which can provide stronger deformation recovery force for this area. Therefore, in the area where stress is concentrated near the bending axis O, a double and stronger structural support and deformation recovery capability can be formed, which helps to further reduce the risk of permanent deformation of the adhesive layer 100, thereby effectively mitigating the crease problem in the bending area F1.

[0089] In some examples, along the direction from the first edge S1 to the bending axis O, the projected area of ​​the first support sub-part 112 in each first sub-region B1 on the support sub-layer 30 can gradually increase, and the projected area of ​​the second support sub-part 212 in each first sub-region B1 on the support sub-layer 30 can gradually increase.

[0090] Understandably, the bending stress in the bending zone F1 gradually increases from the first edge S1 towards the bending axis O. Therefore, setting the projected areas of both the first support sub-part 112 and the second support sub-part 212 to gradually increase accordingly creates a dual adaptation to this stress distribution. Consequently, this provides stronger structural support and deformation recovery capability in areas of higher bending stress in the adhesive layer 100, thereby more effectively reducing the formation of creases in the bending zone F1. Simultaneously, by optimizing overall stress transmission and reducing tensile damage to the adhesive layer 100 caused by localized stress concentration, the problem of crease deepening and diffusion is further improved, thus enhancing the crease resistance of the adhesive layer 100.

[0091] Figure 9 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure.

[0092] like Figure 9 As shown, in some embodiments, the first support sub-sections 112 within the two first regions F11 may be tree-shaped. For example, the first support sub-section 112 includes a main support strip extending along the bending axis O, with short arms extending from both sides of the main support strip to form a multi-level forked structure. Along the direction from the first edge S1 towards the bending axis O, the projected area of ​​the first support sub-section 112 on the support sub-layer 30 may gradually increase.

[0093] Based on this, the first support sub-part 112 can provide multi-directional support and deformation recovery capability during bending. With the gradually increasing projected area, it can better adapt to the stress distribution of the bending area F1, which helps to reduce local stress concentration, thereby improving the crease problem in the bending area F1 and enhancing the crease resistance of the adhesive layer 100.

[0094] It should be noted that, Figure 9 Taking the first support sub-part 112 as an example, the shape of the second support sub-part 212 can be the same as the shape of the first support sub-part 112. Therefore, the shape of the second support sub-part 212 can be referenced. Figure 9 The shape of the first support sub-part 112 shown will not be described again here. In addition, the embodiments of this disclosure are only described using the tree-shaped first support sub-part 112 and second support sub-part 212 as examples, but the shapes of the first support sub-part 112 and second support sub-part 212 provided in the embodiments of this disclosure are not limited to this.

[0095] It is understood that in some other embodiments, the shape of the second support sub-part 212 may be different from the shape of the first support sub-part 112. The shape of the second support sub-part may also adopt the shape described in other embodiments (including but not limited to the shapes mentioned above). For example, the shape of the second support sub-part may be set as a strip or a hollowed-out rhombus, etc.

[0096] Figure 10 This is a schematic diagram of the structure of another first adhesive sublayer provided in an embodiment of the present disclosure.

[0097] like Figure 10 As shown, in some embodiments, the first support sub-parts 112 within the two first regions F11 may be arc-shaped, and each first support sub-part 112 protrudes toward the side of the bending axis O.

[0098] Specifically, along the direction from the first edge S1 to the bending axis O, the length of the first support sub-part 112 gradually increases in the first direction X.

[0099] Based on this, the projected area of ​​the first support sub-part 112 located in the first sub-region B1 near the bending axis O along the direction from the first edge S1 to the bending axis O is correspondingly larger than the projected area of ​​the first support sub-part 112 located in the first sub-region B1 near the first edge S1 on the support sub-layer 30.

[0100] Understandably, on the one hand, the arc-shaped first support sub-part 112 can smoothly transmit bending stress, avoiding local stress concentration caused by sharp corners, and helping to suppress the formation of creases in the bending area F1. On the other hand, the increased projected area along the bending axis O can provide stronger structural support and deformation recovery force in high-stress areas, further improving the problem of crease deepening and diffusion, and enhancing the crease resistance and surface smoothness of the adhesive layer 100 after bending.

[0101] It should be noted that, Figure 10 Taking the first support sub-part 112 as an example, the shape of the second support sub-part 212 can be the same as the shape of the first support sub-part 112. Therefore, the shape of the second support sub-part 212 can be referenced. Figure 10 The shape of the first support sub-part 112 shown will not be described again here. In addition, the embodiments of this disclosure are only described using the arc-shaped first support sub-part 112 and second support sub-part 212 as examples, but the shapes of the first support sub-part 112 and second support sub-part 212 provided in the embodiments of this disclosure are not limited to this.

[0102] It is understood that in some other embodiments, the shape of the second support sub-part 212 may be different from the shape of the first support sub-part 112. The shape of the second support sub-part may also adopt the shape described in other embodiments (including but not limited to the shapes mentioned above). For example, the shape of the second support sub-part may be set as a strip or a hollowed-out rhombus, etc.

[0103] Figure 11 This is a cross-sectional view of another adhesive layer provided in an embodiment of this disclosure.

[0104] In some embodiments, such as Figure 11 As shown, along the second direction Y, the width W12 of the first support sub-part 112 is greater than the width W11 of the first adhesive sub-part 111; and / or, along the second direction Y, the width W22 of the second support sub-part 212 is greater than the width W21 of the second adhesive sub-part 211.

[0105] In some examples, along the second direction Y, the width W12 of the first support sub-part 112 is greater than the width W11 of the first adhesive sub-part 111.

[0106] Based on this, the first support sub-part 112 with a larger elastic modulus is set to a wider width, which is beneficial to enhance the structural support and deformation recovery ability of the adhesive layer 100 in the bending area F1, thereby improving the crease problem and enhancing the crease resistance performance of the adhesive layer 100.

[0107] In other examples, along the second direction Y, the width W22 of the second support portion 212 is greater than the width W21 of the second adhesive portion 211.

[0108] Based on this, the second support sub-part 212 with a larger elastic modulus is set to a wider width, which is beneficial to enhance the structural support and deformation recovery ability of the adhesive layer 100 in the bending area F1, thereby improving the crease problem and enhancing the crease resistance performance of the adhesive layer 100.

[0109] In some other examples, along the second direction Y, the width W12 of the first support sub-part 112 is greater than the width W11 of the first adhesive sub-part 111, and the width W22 of the second support sub-part 212 is greater than the width W21 of the second adhesive sub-part 211.

[0110] Based on this, the first support sub-part 112 and the second support sub-part 212 with larger elastic modulus are both set to a wider width, which can synergistically improve the structural support force and deformation recovery ability of the adhesive layer 100 in the bending area F1, thereby better improving the crease problem and enhancing the crease resistance performance of the adhesive layer 100.

[0111] Figure 12 This is a cross-sectional view of another adhesive layer provided in an embodiment of the present disclosure.

[0112] In some embodiments, such as Figure 12 As shown, along the third direction Z, the first support sub-part 112 overlaps with the second adhesive sub-part 211; and / or, along the third direction Z, the second support sub-part 212 overlaps with the first adhesive sub-part 111.

[0113] In some examples, along the third direction Z, the first support sub-part 112 overlaps with the second adhesive sub-part 211.

[0114] Based on this, by overlapping the first support sub-part 112 of the first bending portion 11 and the second adhesive sub-part 211 of the second bending portion 21, the adhesive layer 100 in the bending area F1 can simultaneously achieve bonding and support in the same space, so that the adhesive layer 100 has both good bonding performance and good deformation recovery ability.

[0115] The positional relationship between the first support sub-part 112 and the second adhesive sub-part 211 in the third direction Z can include the following three cases: The first type: Along the third direction Z, the first support sub-part 112 and the second adhesive sub-part 211 partially overlap.

[0116] The second type: along the third direction Z, the first support sub-part 112 coincides with the second adhesive sub-part 211.

[0117] The third type: Along the third direction Z, the first support sub-part 112 covers the second adhesive sub-part 211. In other words, the orthographic projection of the second adhesive sub-part 211 on the support sub-layer 30 is located within the boundary of the orthographic projection of the first support sub-part 112 on the support sub-layer 30.

[0118] Regardless of which of the three configuration methods is adopted, the first support sub-part 112 and the second adhesive sub-part 211 can overlap in the third direction Z, so that the adhesive layer 100 has both good adhesive performance and good deformation recovery ability.

[0119] In other examples, along the third direction Z, the second support sub-part 212 overlaps with the first adhesive sub-part 111.

[0120] Based on this, by overlapping the second support sub-part 212 of the second bending part 21 and the first adhesive sub-part 111 of the first bending part 11, the adhesive layer 100 in the bending area F1 can be simultaneously bonded and supported in the same space, so that the adhesive layer 100 has both good bonding performance and good deformation recovery ability.

[0121] The positional relationship between the second support sub-part 212 and the first adhesive sub-part 111 in the third direction Z can include the following three cases: The first type: Along the third direction Z, the second support sub-part 212 partially overlaps with the first adhesive sub-part 111.

[0122] The second type: along the third direction Z, the second support sub-part 212 coincides with the first adhesive sub-part 111.

[0123] The third type: Along the third direction Z, the second support sub-part 212 covers the first adhesive sub-part 111. In other words, the orthographic projection of the first adhesive sub-part 111 on the support sub-layer 30 is located within the boundary of the orthographic projection of the second support sub-part 212 on the support sub-layer 30.

[0124] Regardless of which of the three configuration methods is adopted, the second support sub-part 212 and the first adhesive sub-part 111 can overlap in the third direction Z, so that the adhesive layer 100 has both good adhesive performance and good deformation recovery ability.

[0125] In some other examples, along the third direction Z, the first support sub-part 112 overlaps with the second adhesive sub-part 211, and the second support sub-part 212 overlaps with the first adhesive sub-part 111.

[0126] Based on this, the bonding reliability and structural support of the adhesive layer 100 in the bending zone F1 can be further improved, and the deformation recovery ability of the adhesive layer 100 can be better enhanced, so that the adhesive layer 100 has both better bonding performance and better bending recovery effect.

[0127] It should be noted that the overlap between the first support sub-part 112 and the second adhesive sub-part 211 along the third direction Z and the overlap between the second support sub-part 212 and the first adhesive sub-part 111 along the third direction Z have been explained in detail above and will not be repeated here. The two can be arbitrarily combined according to actual needs.

[0128] Figure 13 This is a cross-sectional view of another adhesive layer provided in an embodiment of the present disclosure.

[0129] In some embodiments, such as Figure 13 As shown, along the third direction Z, the first support sub-part 112 and the second support sub-part 212 do not overlap.

[0130] Based on this, along the third direction Z, the first support sub-part 112 in the first bending part 11 and the second support sub-part 212 in the second bending part 21 are dispersed, which helps to disperse the stress generated during the bending process to different areas in the bending area F1, avoid local stress concentration, and thus further improve the bending reliability and structural stability of the adhesive layer 100.

[0131] like Figure 13 As shown, in some embodiments, the flexible display device includes a bent state, in which the bending region F1 is bent toward the light-emitting surface of the flexible display device. Wherein, Figure 13 In the middle, O' represents the bent shaft O (e.g., Figure 3 (As shown) The region where the orthogonal projection along the third direction Z is located.

[0132] In adhesive layer 100, the first adhesive sublayer 10 is located on the side of the second adhesive sublayer 20 closer to the light-emitting surface. The first support portion 112 in the first adhesive sublayer 10 does not overlap with the bending axis O, while the second support portion 212 in the second adhesive sublayer 20 overlaps with the bending axis O.

[0133] Understandably, the first adhesive sublayer 10 is located on the side of the second adhesive sublayer 20 closest to the light-emitting surface. In the bent state, the first adhesive sublayer 10 is located inside the bend of the bending zone F1. Since the inside of the bend needs to undergo shrinkage deformation during the bending process, if the support strength in this area is too high, it is easy to generate large bending resistance, which may even lead to uneven bending or creases and damage after long-term bending.

[0134] Based on this, the first support portion 112 in the first adhesive sub-layer 10 is designed not to overlap with the bending axis O, meaning the first support portion 112 can be positioned away from the area corresponding to the bending axis O where stress is relatively concentrated during bending. This helps reduce the support strength in the area corresponding to the bending axis O of the first adhesive sub-layer 10, allowing for reasonable control of the rigidity on the inner side of the bend. This reduces the bending resistance generated by the support structure on the inner side during bending, resulting in a more balanced stress distribution on the adhesive layer 100 during bending. This not only enables smoother bending but also reduces stress accumulation on the inner side of the bend due to excessive resistance, further improving the bending reliability and structural stability of the adhesive layer 100.

[0135] like Figure 13 As shown, in some embodiments, the flexible display device includes a bent state, in which the bending region F1 bends toward the light-emitting surface of the flexible display device.

[0136] In the adhesive layer 100, the first adhesive sublayer 10 is located on the side of the second adhesive sublayer 20 closer to the light-emitting surface. The elastic modulus of the first adhesive sublayer 10 is greater than that of the second adhesive sublayer 20.

[0137] It is understandable that the first adhesive sublayer 10 is located on the side of the second adhesive sublayer 20 closer to the light-emitting surface. In the bent state, the first adhesive sublayer 10 is located on the inner side of the bend in the bending area F1. The inner side of the bend is prone to shrinkage deformation during repeated bending. If the deformation recovery ability is weak, it may not be conducive to the improvement of creases, and may even affect the smoothness of the appearance after bending.

[0138] Based on this, in this embodiment, the elastic modulus of the first adhesive sublayer 10 can be set to be greater than that of the second adhesive sublayer 20. By making the first adhesive sublayer 10, which is located on the inside of the bend, have a relatively larger elastic modulus, it can have a better deformation recovery ability and is more likely to return to its initial state after bending. This helps to reduce the creases that may occur after bending and improves the bending reliability and appearance of the adhesive layer 100.

[0139] like Figure 13 As shown, in some embodiments, along the third direction Z, the thickness of the first adhesive sublayer 10 is d1, the thickness of the second adhesive sublayer 20 is d2, and the thickness of the support sublayer 30 is d3. The thicknesses of the three sublayers satisfy the following relationship: d1 + d2 ≤ d3.

[0140] Understandably, the support sublayer 30, as the main support structure of the adhesive layer 100, possesses a relatively high elastic modulus, which inherently provides stronger structural stability and resistance to deformation. Therefore, by making the support sublayer 30, with its higher elastic modulus, thicker, the overall structural stiffness and load-bearing capacity of the adhesive layer 100 can be further enhanced. This allows for more effective dispersion of stress generated during external impacts, compression, or bending, reducing the risk of structural damage caused by localized stress concentration, thus giving the adhesive layer 100 better impact resistance. Simultaneously, this structural design also helps reduce plastic deformation of the adhesive layer 100 during bending, lowering the possibility of irreversible deformation due to repeated bending, thereby reducing creases after bending and improving the overall stability of the adhesive layer 100 during use.

[0141] like Figure 13 As shown, in some examples, d1=d2.

[0142] Based on this, the thickness d1 of the first adhesive sublayer 10 and the thickness d2 of the second adhesive sublayer 20 can be set to be equal, which is beneficial to make the stress distribution of the adhesive layer 100 in the third direction Z more balanced, and the overall stress during bending more stable, thereby further improving the structural stability and bending reliability of the adhesive layer 100.

[0143] Figure 14 This is a cross-sectional view of another adhesive layer provided in an embodiment of the present disclosure.

[0144] like Figure 14 As shown, in some embodiments, the first adhesive sublayer 10 further includes a first flattening portion 12 located in the non-bending region F2, the elastic modulus of the first flattening portion 12 being less than or equal to the elastic modulus of the first adhesive sublayer 111; and / or; the second adhesive sublayer 20 further includes a second flattening portion 22 located in the non-bending region F2, the elastic modulus of the second flattening portion 22 being less than or equal to the elastic modulus of the second adhesive sublayer 211.

[0145] In some examples, the first adhesive sublayer 10 also includes a first flattening portion 12 located in the non-bending region F2, the elastic modulus of the first flattening portion 12 being less than or equal to the elastic modulus of the first adhesive sublayer 111.

[0146] This configuration ensures that the overall elastic modulus of the first adhesive sublayer 10 in the bending zone F1 is not less than the elastic modulus of the non-bending zone F2. This is beneficial to improving the deformation recovery capability of the first adhesive sublayer 10 in the bending zone, making it easier for the first adhesive sublayer 10 to return to its initial state after bending. This improves creases and enhances the bending reliability and appearance flatness of the adhesive layer 100.

[0147] In other examples, the second adhesive sublayer 20 also includes a second flattening portion 22 located in the non-bending region F2, the elastic modulus of the second flattening portion 22 being less than or equal to the elastic modulus of the second adhesive sublayer 211.

[0148] This configuration ensures that the overall elastic modulus of the second adhesive sublayer 20 in the bending zone F1 is not less than the elastic modulus of the non-bending zone F2. This is beneficial for improving the deformation recovery capability of the second adhesive sublayer 20 in the bending zone, making it easier for the second adhesive sublayer 20 to return to its initial state after bending. This improves creases and enhances the bending reliability and appearance flatness of the adhesive layer 100.

[0149] In some other examples, the first adhesive sublayer 10 further includes a first flattening portion 12 located in the non-bending region F2, the elastic modulus of the first flattening portion 12 being less than or equal to the elastic modulus of the first adhesive sublayer 111. Furthermore, the second adhesive sublayer 20 further includes a second flattening portion 22 located in the non-bending region F2, the elastic modulus of the second flattening portion 22 being less than or equal to the elastic modulus of the second adhesive sublayer 211.

[0150] This configuration ensures that the overall elastic modulus of the adhesive layer 100 in the bending zone F1 is not less than that in the non-bending zone F2. This is beneficial for improving the deformation recovery capability of the adhesive layer 100 in the bending zone, making it easier for the adhesive layer 100 to return to its initial state after bending. This improves creases and enhances the bending reliability and appearance flatness of the adhesive layer 100.

[0151] The present invention does not impose any special limitation on the thickness of the adhesive layer 100. For example, the thickness of the adhesive layer 100 can be 25μm or 50μm. However, 25μm and 50μm are only examples for illustration. The present invention does not limit the thickness of the adhesive layer 100 to this. In actual applications, it can be adjusted according to the specific structural adaptability of the flexible display device.

[0152] It is understood that the adhesive layer 100 provided in any of the above embodiments can be formed by layering and curing, with the specific steps as follows: First, the material corresponding to the support sub-layer 30 is coated and cured. The support sub-layer 30 can play an impact-resistant role and provide a stable base for the subsequent sub-layer formation. Then, the adhesive reinforcement material corresponding to the adhesive sub-part (which can cover the area that needs to be formed to enhance the recovery rate during the coating process) is coated and cured. The formed adhesive sub-part includes the first adhesive sub-part 111 in the first bending part 11 and the second adhesive sub-part 211 in the second bending part 21 to ensure the bonding reliability between the adhesive layer 100 and the adjacent functional layer. Finally, the material corresponding to the support sub-part is coated on the previously covered recovery rate enhancement area to form a support sub-part including the first support sub-part 112 in the first bending part 11 and the second support sub-part 212 in the second bending part 21. The support sub-part can improve the deformation recovery capability of the adhesive layer 100.

[0153] It should be noted that the above preparation method is only an illustrative example, and the preparation method of adhesive layer 100 in this embodiment is not limited thereto. In actual preparation, the formation sequence, coating method, curing process, etc. of each sub-layer can be adaptively adjusted according to the material characteristics, process conditions and product structure requirements, as long as an adhesive layer 100 including support sub-layer 30, first adhesive sub-part 111, second adhesive sub-part 211, first support sub-part 112 and second support sub-part 212 can be formed, and the corresponding impact resistance, bonding and deformation recovery functions can be achieved.

[0154] Figure 15 This is a cross-sectional view of a display device provided in an embodiment of the present disclosure.

[0155] like Figure 15 As shown, this disclosure provides a display device 200, which includes a plurality of functional layers 300 and at least one adhesive layer 100. At least two adjacent functional layers 300 are bonded together using the adhesive layer 100. The adhesive layer 100 can be any of the adhesive layers 100 provided in the preceding embodiments.

[0156] Figure 1 and Figure 15 The embodiments described herein use only a mobile phone as an example to illustrate the flexible display device 200. It is understood that the flexible display device 200 provided in this disclosure can be other flexible display devices 200 with display functions, such as computers, televisions, and automotive display devices; this disclosure does not impose specific limitations on these. The flexible display device 200 provided in this disclosure has the beneficial effects of the adhesive layer 100 provided in this disclosure. For details, please refer to the specific descriptions of the adhesive layer 100 in the above embodiments; these descriptions will not be repeated here.

[0157] like Figure 15 As shown, in some embodiments, the multiple functional layers 300 may include: a flexible cover plate 310, a buffer layer 320, a protective layer 330, a display panel 340, a back plate 350, a first support layer 360, and a second support layer 370.

[0158] The adhesive layer 100 can be disposed between any two adjacent functional layers 300 for fixing and bonding the two adjacent functional layers 300.

[0159] For example, the adhesive layer 100 can be located between the flexible cover plate 310 and the buffer layer 320 to fix and bond the flexible cover plate 310 and the protective layer 330.

[0160] For example, the adhesive layer 100 can be located between the buffer layer 320 and the protective layer 330 to fix and bond the buffer layer 320 and the protective layer 330.

[0161] For example, adhesive layer 100 can be located between protective layer 330 and display panel 340 to fix and bond protective layer 330 and display panel 340.

[0162] For example, adhesive layer 100 can be located between display panel 340 and back panel 350 for fixing and bonding display panel 340 and back panel 350.

[0163] For example, the adhesive layer 100 can be located between the back plate 350 and the first support layer 360 to fix and bond the back plate 350 and the first support layer 360.

[0164] For example, the adhesive layer 100 can be located between the first support layer 360 and the second support layer 370 for fixing and bonding the first support layer 360 and the second support layer 370.

[0165] Based on this, by providing the adhesive layer 100 described in this disclosure between each adjacent functional layer 300, the bending area F1 (e.g., ...) can be effectively enhanced during bending. Figure 1 The deformation recovery capability (as shown) reduces the risk of permanent deformation of the adhesive layer and adjacent film layers, thereby effectively reducing the creases in the bending area F1 of the display device 200 and improving bending reliability and appearance flatness.

[0166] In some examples, the flexible cover plate 310 can be made of a transparent polyimide film (Colorless Polyimide, CPI). CPI has high light transmittance, good bending resistance and structural strength, and as an outer cover plate, it helps to maintain the appearance and structural stability during bending. Combined with the adhesive layer 100 in any of the above embodiments, it can improve the deformation recovery ability of the bending area F1 and reduce creases.

[0167] In some examples, the material of the buffer layer 320 can be a thermoplastic polyurethane (TPU) elastomer film. TPU has good flexibility, buffering energy absorption and resilience properties, and can absorb bending stress to a certain extent. Combined with the adhesive layer 100 in any of the above embodiments, it can optimize the stress dispersion effect in the bending area F1, reduce the possibility of permanent deformation, and improve creases.

[0168] In some examples, the protective layer 330 can be made of polyethylene terephthalate (PET) film. PET has good strength, flatness, and optical stability. In some embodiments, it can replace traditional polarizers to simplify stacking. Combined with the adhesive layer 100 in any of the above embodiments, it can improve the structural stability of the bending area F1 and reduce creases.

[0169] In some examples, the display panel 340 may be one of an OLED (Organic Light Emitting Diode) display panel, a QLED (Quantum Dot Light Emitting Diodes) display panel, or a microLED (including MiniLED or MicroLED, where LED is a light-emitting diode) display panel.

[0170] In some examples, the material of the first support layer 360 can be a polyimide film (PI). PI, as a support layer, can provide reliable support for the display device 200 and effectively disperse the concentrated stress in the bending area F1 during bending. When used in conjunction with the adhesive layer 100 provided in any of the above embodiments, it can further enhance the deformation resistance of the bending area F1 and reduce the generation and residue of creases.

[0171] In some examples, the second support layer 370 can be made of stainless steel (SUS). SUS, as a metal support layer, provides strong structural support for the display device 200, significantly enhancing the rigidity and deformation resistance of the bending zone F1, and effectively dispersing concentrated stress near the bending axis during bending. The adhesive layer 100, used in conjunction with any of the above embodiments, can improve deformation recovery efficiency and reduce the risk of crease formation.

[0172] Understandably, in order to improve the light transmittance of the flexible display device 200, the material of the adhesive layer 100 disposed on the light-emitting side of the display panel 340 can be selected as OCA, while the material of the adhesive layer 100 disposed on the backlight side of the display panel 340 can be selected as PSA.

[0173] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0174] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An adhesive layer, characterized in that, The invention is applied to a flexible display device having a bending region and a non-bending region located on at least one side of the bending region; the bending region includes a bending axis extending along a first direction. The adhesive layer includes: a first adhesive sublayer, a second adhesive sublayer, and a support sublayer, wherein the support sublayer is located between the first adhesive sublayer and the second adhesive sublayer; The first adhesive sublayer includes a first bent portion located in the bending region. Along the second direction, the first bent portion includes alternating first adhesive sub-parts and first support sub-parts. The elastic modulus of the first support sub-parts is greater than that of the first adhesive sub-parts, and the elastic modulus of the first support sub-parts is less than that of the support sublayer. The second adhesive sublayer includes a second bent portion located in the bending region. Along the second direction, the second bent portion includes alternately arranged second adhesive sub-parts and second support sub-parts. The elastic modulus of the second support sub-part is greater than that of the second adhesive sub-part, and the elastic modulus of the second support sub-part is less than that of the support sublayer. Wherein, the second direction intersects with the first direction, and the second direction also intersects with the thickness direction of the adhesive layer.

2. The adhesive layer according to claim 1, characterized in that, The bending area includes two first regions located on both sides of the bending axis; Both of the first regions are provided with the first support sub-parts, and the first support sub-parts in both of the first regions are symmetrically arranged along the bending axis; and / or; The second support sub-parts are provided in both of the first regions, and the second support sub-parts in the two first regions are symmetrically arranged along the bending axis.

3. The adhesive layer according to claim 1, characterized in that, The first support sub-part has an axisymmetric structure, and the axis of symmetry of the first support sub-part is parallel to the bending axis; and / or; The second support sub-part has an axisymmetric structure, and the axis of symmetry of the second support sub-part is parallel to the bending axis.

4. The adhesive layer according to claim 1, characterized in that, The bending area includes two first regions located on both sides of the bending axis; along the second direction, the bending area includes two opposing first edges, and along the direction from the first edges toward the bending axis, the first region includes a plurality of first sub-regions; Along the direction from the first edge toward the bending axis, the projected area of ​​the first support sub-part within the first sub-region near the bending axis on the support sub-layer is greater than the projected area of ​​the first support sub-part within the first sub-region near the first edge on the support sub-layer; and / or, Along the direction from the first edge toward the bending axis, the projected area of ​​the second support sub-part in the first sub-region near the bending axis on the support sub-layer is greater than the projected area of ​​the second support sub-part in the first sub-region near the first edge on the support sub-layer.

5. The adhesive layer according to claim 1, characterized in that, Along the second direction, the width of the first support sub-part is greater than the width of the first adhesive sub-part; and / or, Along the second direction, the width of the second support sub-part is greater than the width of the second adhesive sub-part.

6. The adhesive layer according to claim 1, characterized in that, Along the thickness direction of the adhesive layer, the first support sub-part and the second adhesive sub-part overlap; and / or, Along the thickness direction of the adhesive layer, the second support sub-part overlaps with the first adhesive sub-part.

7. The adhesive layer according to claim 1, characterized in that, Along the thickness direction of the adhesive layer, the first support sub-part and the second support sub-part do not overlap.

8. The adhesive layer according to claim 1, characterized in that, The flexible display device includes a bent state, in which the bent area is bent toward the light-emitting surface of the flexible display device. The first adhesive sublayer is located on the side of the second adhesive sublayer closer to the light-emitting surface; In the first adhesive sublayer, the first support portion does not overlap with the bending axis, while in the second adhesive sublayer, the second support portion overlaps with the bending axis.

9. The adhesive layer according to claim 1, characterized in that, The flexible display device includes a bent state, in which the bent area is bent toward the light-emitting surface of the flexible display device. The first adhesive sublayer is located on the side of the second adhesive sublayer closer to the light-emitting surface; The elastic modulus of the first adhesive sublayer is greater than that of the second adhesive sublayer.

10. The adhesive layer according to claim 1, characterized in that, The sum of the thicknesses of the first adhesive sublayer and the second adhesive sublayer is less than or equal to the thickness of the support sublayer.

11. The adhesive layer according to claim 1, characterized in that, The first adhesive sublayer further includes a first flat portion located in the non-bending region, wherein the elastic modulus of the first flat portion is less than or equal to the elastic modulus of the first adhesive sublayer; and / or; The second adhesive sublayer also includes a second flattened portion located in the non-bending area, wherein the elastic modulus of the second flattened portion is less than or equal to the elastic modulus of the second adhesive sublayer.

12. The adhesive layer according to claim 1, characterized in that, The adhesive layer is an optical adhesive or a pressure-sensitive adhesive.

13. A flexible display device, characterized in that, include: Multiple functional layers, wherein at least two adjacent functional layers employ the aforementioned claim 1. The adhesive layer described in any one of 12 is bonded together.

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